Lithium dendrite suppression by single-ion conducting gel polymer electrolyte cross-linked with graphene oxide

Abstract

This study presents a preparation of single-ion conducting gel polymer electrolytes (SPGEs) and their application for lithium metal battery systems. SGPEs are prepared by an in-situ cross-linking reaction of methacrylategraphene oxide (MGO) and lithium cation conducting monomer (LiMTFSI) using poly(vinylidene fluoride-co- hexafluoropropylene) (PVH) as a matrix polymer. The SGPEs prepared by the in-situ cross-linking reaction with MGO are found to have highly porous structure leading to the high liquid electrolyte uptake and high ionic conductivity. The cross-linked SGPEs show improved mechanical strength, thermal and electrochemical stability compared with the SGPE without any MGO cross-linker. In addition, lithium dendrite growth is successfully suppressed by the cross-linked SGPE because it contains single ion conducting LiMTFSI moiety and MGO cross linker having 2D structure with many lithiophilic moieties. As a result, lithium metal batteries assembled with SGPE show much improved cycle performance compared to the conventional Celgard-liquid electrolyte system.